Interesting question. Those who say that elders with dementia cannot feel pain ( or recently, I heard they cannot feel itchy??), or they won't remember trauma are sorely mistaken. They may forget the details, but the emotion will linger, and they may be agitated for no apparent reason. They may have flashback and delusions that come from the trauma. In addition, if they are abused, emotionally, physically, they may not understand the details, but can be terrorized. That said. Trauma, whether adverse childhood events, natural disasters, or other crises, from being victim of a crime to chronic abuse from a bad personal relationship (spouse, family, employer etc) can increase cortisol. Increased stress hormones can lead to depression, increased hypertension, worse medical outcomes and related to increased risk of dementia. That said, a supportive relationship can be very healing in the face of adversity.